Gasket compression in metal housings and assemblies can support sealing or contribute to gasket failure. That’s because rubber gaskets are resilient, but only to a point. Compressing a gasket within allowable limits forms a reliable seal. When a gasket is over-compressed, however, the rubber won’t rebound when the compressive stresses are removed. This creates a gap between the gasket and the surface of the housing or assembly. Gaps cause leaks, and seals that leak won’t support your designs.
Material scientists calls the permanent deformation of the gasket material “compression set”, a term that’s used widely but not always fully understood. Engineers need to know the basics of compression set, but they also need to consider its limitations as a test method. With housings and assemblies, it’s essential to account for the entire application environment, including variables such as temperature and vibration. Relaxation, a related phenomenon, is also associated with gasket compression. (more…)